import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    static int minimumNumber(int n, String password) {
        // Return the minimum number of characters to make the password strong
        int i=0;
        int f1=0,f2=0,f3=0,f4=0,c=0;
        for(i=0;i<n;i++)
        {
            if(password.charAt(i)>='a' && password.charAt(i)<='z')
                f1=1;
             else if(password.charAt(i)>='A' && password.charAt(i)<='Z')
                f2=1;
             else if(password.charAt(i)>='0' && password.charAt(i)<='9')
                f3=1;
            else if(password.charAt(i)=='!'||password.charAt(i)=='@'||password.charAt(i)=='#'||password.charAt(i)=='$'||password.charAt(i)=='%'
                    ||password.charAt(i)=='^'||password.charAt(i)=='&'||password.charAt(i)=='*'||password.charAt(i)=='('||password.charAt(i)==')'
                    ||password.charAt(i)=='+'||password.charAt(i)=='-')
                f4=1;
        }
        if(f1==0)
            c++;
        if(f2==0)
            c++;
        if(f3==0)
            c++;
        if(f4==0)
            c++;
        if(n>=6)
            return c;
        else
        {
            if(n+c<6)
                return 6-n;
            else
                return c;
                
        }
        
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        String password = in.next();
        int answer = minimumNumber(n, password);
        System.out.println(answer);
        in.close();
    }
}